A passive optical network (PON) is one system for providing network access over “the last mile.” The PON is a point to multi-point network comprised of an optical line terminal (OLT) at the central office, an optical distribution network (ODN), and a plurality of optical network units (ONUs) at the customer premises. Downstream data transmissions may be broadcast to all of the ONTs, while upstream data transmissions may be transmitted to the OLT using time division multiple access (TDMA). TDMA ensures transmissions from the ONUs are received by the OLT one at a time and do not conflict with one another.
Because the per-user capacity of TDMA-based PONs is inversely proportional to the quantity of users, there is considerable interest in wavelength division multiple access (WDMA)-based PONs. WDMA-based PONs permit greater speeds by virtue of the numerous available wavelengths, but employ components which are undesirably expensive. Specifically, the lasers used in WDMA-based PONs must be fully-tunable in that they must be able to maintain a specific wavelength. Fully-tunable lasers require a complicated temperature control apparatus, and consequently are expensive and difficult to manufacture and operate. Thus, a need exists for a WDMA-based PON that does not require fully-tunable lasers.